Goodell's ruling last Thursday caused a harsh backlash from critics who thought he let Rice off lightly compared to harsher penalties for doping and on-field violations by other players.

Three U.S. senators expressed their dismay in a letter to Goodell that the punishment did not send a strong enough message against domestic violence.

"Our policy is clear. We have very firm policy that domestic violence is not acceptable here in the NFL and there will be consequences for that," Goodell told reporters in Canton, Ohio, site of Saturday's Hall of Fame inductions.

"(Rice) has been accountable for his actions. He recognizes he made a horrible mistake that is unacceptable by his standards, by our standards, and he's got to work to re-establish himself," Goodell said.

"The criminal justice system...put him in a diversionary program with no discipline, and we felt it was appropriate to have discipline and to continue counseling programs and to continue our educational work."

Rice was arrested in February after an altercation with his then-fiancée Janay Palmer at an Atlantic City hotel.

Video surfaced online showing Rice dragging an apparently unconscious Palmer out of the hotel elevator. The couple has since married.

Rice pleaded not guilty to a third-degree charge of aggravated assault and avoided trial by being accepted into an intervention program in May.

The running back, who helped the Ravens win the Super Bowl in 2013, issued an emotional apology in a news conference at the team's training camp on Thursday.

"I was also very impressed with Ray in the sense that Ray is not only accepting this issue in saying 'I was wrong' but he's saying I want to make a powerful difference in this area," said Goodell, pointing out that this is Rice's first violation of any league policy.

"I think you heard from him yesterday and he's a young man that really understands the mistake he made and he's bound and determined to make a positive difference."